The ISM 900 MHz band ranges from 902 MHz to 928 MHz. Products offered in this band by numerous manufacturers include simple applications like a baby monitor or a garage door opener to more sophisticated products like a nationwide mobile VOIP solution. For devices using a time division duplex scheme, there is a critical need to receive and transmit data slots in an uninterrupted fashion. A MIMO transceiver can increase the probability of useful Signal to Noise Ratio (SINR) using Maximum Ratio Combining (MRC) and other combining methods. To achieve the above-mentioned transmissions the MIMO transceiver needs non-correlated channels at each of its receivers. The MIMO antenna array proposed produces 4 by 4 uncorrelated paths thru use of spatial diversity.
An antenna is a critical part of any wireless transceiver device. There are any number of different types of antennae each tuned for specific frequency bands and applications. Antenna parameters such as radiation pattern, bandwidth, gain, physical size, and realization techniques are dependent on specific applications. Mobile communication devices sometimes use multiband antennae (all integrated into one single antenna) that cover a variety of frequency bands. Gain, cost, and size of the antenna are important factors when designing antennae for mobile transceiver devices. Realization techniques for such antennae have varied over the years from simple wire type (fixed or telescopic) to more sophisticated chip antennae or printed circuit antennae with various assembly techniques ranging from simple printed circuit board mounted antennae to more complicated flip mechanical assemblies.
With more MIMO transceiver designs and OFDM transmissions to combat fading being used in wireless communications, a typical simple antenna arrangement will not meet the above mentioned requirements and a new MIMO antenna design is needed.